NANOTUBES: Confined water and Stability under Pressure

Abstract: Motivated by our recent observations[1] that flow of water on single walled carbon nanotubes can generate electrical current , we seek experimental answer to the question if water can enter the nanotubes of diameter about 1nm.This is done using nuclear magnetic resonance which shows clearly that the water does enter the nanotubes and freezes at temperatures below -50 C. Most interestingly the dynamics shows single file diffusion , in contrast to bulk diffusion. The second part of the talk will present our recent studies on pressure -induced transformations in Boron Nitride multiwall nanotubes.Using Raman scattering we will show that unlike carbon nanotubes, BN nanotubes irreversibly transform at high pressures[2].This motivated us to carry out molecular dynamics simulations to understand the stability of nanotubes under pressure[3].We will discuss our recent results. [1] S Ghosh,A K Sood and N Kumar, Science 299,1042(2003). [2] S Saha et al Chem Physics Lett. 421,86(2006). [3] V Gadagkar et al Phys Rev B 73,85402(2006). ------------------------------------------------------------------------ Séminaire de Minéralogie ------------------------------------------------------------------------